What does Grint have to do with whom Hermione chose? This secret went from A to Q pretty damn quickly.

That being said, there are plenty of reasons why she chose Ron; in fact there are essay out there explaining it quite well, so I'm not going to sit here and get into the details of it. Of all the characters we're shown in HP, Ron was the best suited one for what Hermione wanted and needed (someone who challenged her and pushed her), so outside of an unnamed character, Ron was her match.

I mean, she fell for her best friend, which is one of the oldest plotlines in literature.